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  1. #171

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    Quote Originally Posted by albada View Post
    DS-10 and XTOL get some of their fine grain from the solvent-effect of Sodium Sulfite, and we need a substitute for Sodium Sulfite that'll dissolve in Propylene Glycol. That's why I was looking at solvents.
    I suggest to scrap that line of effort. The logic is right, but that line of ideas have been tried and retried a great many times, some by myself. Many chemists still prefer sodium sulfite.

  2. #172

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    Quote Originally Posted by Gerald C Koch View Post
    Haist mentions the amino acid cysteine as a silver halide solvent. I know that the amino acid arginine is also a silver halide solvent as it interferes with the classical analysis for chloride with Ag+. Both are available in health food stores as a powder at reasonable prices. They should be soluble in glycols. Cysteine contains a thiol (-SH) group along with many other chemicals which accounts for the halide solvency. Arginine has several amine groups which accounts for its solvency affect. Of the two mentioned cysteine is probsbly better as a first choice.
    What you don't realize is that cysteine deteriorates gelatin. I wouldn't use it in practical processing solution. When reading literature, you always have to keep practical factors in mind.

  3. #173

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    Quote Originally Posted by albada View Post
    Would this buffer be effective if those molecules have formed esters with the PG? If not, omitting the boric acid and reducing the metaborate would permit a greater concentration.

    BTW, I want to thank those who've posted helpful suggestions in this thread, especially Ron (PE) and Jerry. You guys are a lifesaver! There's no way I could have gotten to this point so quickly (or at all?) without your help.
    Another piece of dangerous half knowledge. Ester of borates with polyols is a very slow reaction that needs to be accelerated to be practical, but then the reaction is condensation reaction. Dilute your mixture in water and it will be undone in a moment. Nothing to worry about.

    Incidentally, ascorbates can form ester with borates if properly reacted. Again, it is not a concern with aquaous developer solutions.

  4. #174

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    Guys,

    Hereís what I think after reading this long thread.

    If your purpose is to tinker about basic chemistry, I think you can find more fun and easier projects to learn basics. Developer chemistry is complex, yet not very rewarding because there are so many rigid and exacting requirements for practical developers, and then any difference in developers is not going to make a night-and-day difference in photography. A new developers just provide another way to arrive at the same result. Most of you already spent more effort being on this topic than the entire amount of effort that could be saved by being able to avoid weighing powder sulfite and ascorbate each time you develop film.

    If you are trying to make money by coming up with a great product, it wouldnít be a darkroom product, either. There is no money in darkroom products. At this point and time, there is not. One answer is skin care products, cosmetics and pharmaceuticals.

    If you are genuinely trying to make some difference in photographic chemistry, why donít you tackle a new challenge that no existing formula adequately dealt with? Still, the golden era of developer chemistry will not come again. Itís not lack of your million dollar budget. It is the result of what we already know from the past research and what we will probably never find out due to known difficulties. The current film based imaging is rather perfected in many ways, and there is little room to improve upon.

    So, why donít you pick up a camera and shoot more film? Kodak and Fujifilm need you. Kodak will raise the price in a few months. Time to burn some old stocks and buy more bricks.

  5. #175

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    Quote Originally Posted by Ryuji View Post
    If your purpose is to tinker about basic chemistry, I think you can find more fun and easier projects to learn basics.
    I shoot maybe one roll a month in 35mm, and I can't use my 5 liters of XTOL before it goes bad. A concentrate that gives XTOL-quality would be perfect for hobbyist-shooters like me, but no major manufacturer makes one. Even if a small company made one, I wouldn't feel comfortable because: What happens if the little company closes? My developer vanishes. So I want the concentrate to either (1) be made by a large company, or (2) have a published formula so I can mix it myself (in case the company vanishes).

    Also, I enjoy learning about new things. And sometimes I invent something useful. Here's an example:
    http://drdobbs.com/tools/229625477

    For hobbyist shooting, there is no problem mixing the sulfite separately, as you suggested, which makes designing a concentrate easier.

    Anyway, thanks for responding. Did you try cysteine and discover it damages gelatin? I don't have Haist's monobath book, so I don't know what he reported about it.

    Mark Overton

  6. #176

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    Quote Originally Posted by Ryuji View Post
    I suggest to scrap that line of effort. The logic is right, but that line of ideas have been tried and retried a great many times, some by myself. Many chemists still prefer sodium sulfite.
    Tests on this line of ideas are not described here on APUG as far as I know.
    It would be interesting to know if you tried the grain solvent ammonium thiocyanate as it is available and not expensive.Particularly,will it dissolve in glycol,are there associated hazards and why it was not used.

  7. #177
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    Actually, thiocyanates are a good idea as are Mono Ethanol Amine and Di Ethanol Amine. Potassium Sulfite comes to mind as it is very much more soluble in water and some other solvents than is the Sodium salt.

    And in Edens and Mowrey, what is NOT said is important. HAS (Hydroxyl Amine Sulfate) and its successor Di Ethyl Hydroxyl Amine Oxalate are very soluble and do inhibit oxidation of AA/PD developers. I have not come to a full conclusion on this, as my tests had to stop too early due to emulsion work, but HAS does stabilize.

    So, there are hints for you Mark.

    There were 2 paths being undertaken in the late 80s by Bill Lee and others who wished to make a better version of XTOL or HC110. This work was terminated in about 1988, but the experimental formulas are still rattling around in my head. They all used things mentioned here as well as things not mentioned. Most was the combination of the above ingredients in new ways.

    One key I can tell you of is that the best of all possible worlds is slow development with long times. This maximizes speed and sharpness while minimizing grain. But then, that should not be news to those of you using 1 hour development times. So consider a known formula but reduced in potency to achieve a slow rate of development.

    PE

  8. #178

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    Quote Originally Posted by Ryuji View Post
    So, why donít you pick up a camera and shoot more film? Kodak and Fujifilm need you. Kodak will raise the price in a few months. Time to burn some old stocks and buy more bricks.
    Yes, Kodak, Fuji, and Ilford need us to buy their film. Shoot enough film and you don't have to worry about developers going bad. Two birds, one stone.

    Happy holidays to all and a prosperous New Year!!!

    Jerry
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  9. #179

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    Quote Originally Posted by albada View Post
    A concentrate that gives XTOL-quality would be perfect for hobbyist-shooters like me, but no major manufacturer makes one.
    You might want to know that formulating a good developer is one thing, but formulating a good developer that can be prepared as a concentrated solution is a different thing.

    When Silvergrain products were offered commercially, I was strongly advocating among those who were involved to offer powder solutions. They are more green (why do you want to burn extra fuel to carry water and heavier packaging for products that have shorter shelf life?), TSA-friendly, and better formulations can be made. All my proposals were roundly rejected because the consumers are obsessed with the notion of liquid concentrates are superior performers. At this point and time when majority of users are small volume users like you, I really think all powder formula make more sense.

    Even if a small company made one, I wouldn't feel comfortable because: What happens if the little company closes? My developer vanishes. So I want the concentrate to either (1) be made by a large company, or (2) have a published formula so I can mix it myself (in case the company vanishes).
    You are assuming business people are rational. At this point and time, majority of smart business people already left, forced to leave and/or abandoned silver halide imaging industry. So the only players are the people with limited business expertise who are fighting for the few remaining pennies. They often donít make rational judgments.

    For hobbyist shooting, there is no problem mixing the sulfite separately, as you suggested, which makes designing a concentrate easier.
    Right. Or, as I said above, reconsider all powder formulation.

    Did you try cysteine and discover it damages gelatin?
    How else would I know? Keep in mind photographic industry is very notorious for not disclosing anything useful unless it is absolutely required to get patents. Many patents have serious flaws but they do not disclose such things until they solve them, at which point they reveal the problem only as a basis for a new patent application. Iíve read MANY patents and repeated many examples given in the patents just to find out the limitation of their inventions. Haistís books are largely compiled from benign published materials including patents, and the manuscript was betted by several Eastman employees just like the CIA and the state department redact documents they release.

    Cysteine, thiourea, thiocyanate, etc. all have adverse effects on gelatin. This is largely pH and concentration dependent. But really, another problem with these agents is loss of speed with modern films. If you accept the loss of speed, you could achieve matching granularity by cutting development time or some other means. Some of these legendary "fine grain agents" actually make grains bigger with modern films, depending on the developer formula. Another problem with this type of agents is loss of accutance. If your objective is to achieve maximum enlargeability, it is not just granulrity that impose limitation. Besides, these agents also tend to produce strange sensitometric curves with some modern films, and also increase the tendency to cause silver stains such as dichroic fog. All these problems are not worth fighting for.
    Last edited by Ryuji; 12-24-2011 at 04:08 PM. Click to view previous post history.

  10. #180

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    Quote Originally Posted by Alan Johnson View Post
    Tests on this line of ideas are not described here on APUG as far as I know.
    APUG didn't exist back then. Also, it is not a common practice to report negative results unless they resolve a controversy or something.

    It would be interesting to know if you tried the grain solvent ammonium thiocyanate as it is available and not expensive.Particularly,will it dissolve in glycol,are there associated hazards and why it was not used.
    See my previous response.



 

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